Frog ‘saunas’ provide crucial support for endangered frog populations

Introduction

Macquarie University researchers, in collaboration with the University of Melbourne, have developed a simple and effective method to help endangered frogs survive the devastating impacts of chytridiomycosis, a fungal disease that threatens multiple amphibian species globally. Chytridiomycosis, caused by the chytrid fungus Batrachochytrium dendrobatidis (Bd), has been a significant driver of global amphibian population declines over the past 25 years. This disease has already driven at least six amphibian species to extinction in Australia and poses a severe threat to dozens more worldwide. Once established in a new environment, the chytrid fungus becomes a permanent fixture, making it one of the most damaging pathogens to global biodiversity. The new method developed by these researchers represents a potential lifeline for critically affected populations, such as the green and golden bell frog (Litoria aurea), which has vanished from over 90 percent of its former native range in Australia.

The findings, published in the journal Nature on June 26, 2024, offer significant hope for these fast-declining amphibian populations. Dr. Anthony Waddle, a Schmidt Science Fellow at Macquarie University’s Applied BioSciences and the lead author of the study, emphasizes the groundbreaking nature of their work: “In the 25 years since chytrid was identified as a major cause of the global collapse of amphibian populations, our results are the first to provide a simple, inexpensive, and widely applicable strategy to buffer frogs against this disease.” The research team discovered that artificial ‘hotspot’ shelters made from readily available materials, such as bricks and PVC greenhouses, allow frogs to heat their bodies to a temperature that destroys the fungal infections. This approach not only reduces chytrid infections significantly but also helps surviving frogs develop a form of acquired immunity, making them more resistant to future infections. Senior author Professor Rick Shine from Macquarie University’s School of Natural Sciences highlights the scalability of this intervention, noting that these simple shelters can be easily reproduced and implemented with community involvement, potentially helping to reduce the impact of the deadly chytrid pandemic on endangered amphibian species globally.

The Threat of Chytridiomycosis

Chytridiomycosis, caused by the chytrid fungus Batrachochytrium dendrobatidis (Bd), has been identified as a major driver of global amphibian population declines over the past 25 years. This disease has led to the extinction of at least six amphibian species in Australia and threatens dozens more worldwide. The fungus typically establishes itself permanently in new environments, making it one of the most damaging diseases to global biodiversity.

Chytridiomycosis: Caused by the chytrid fungus Batrachochytrium dendrobatidis (Bd)
Impact: Major driver of global amphibian population declines over the past 25 years
Extinctions: Led to the extinction of at least six amphibian species in Australia
Threat: Endangers dozens more species worldwide
Permanence: Fungus typically establishes itself permanently in new environments
Biodiversity: One of the most damaging diseases to global biodiversity

Innovative Heat Treatment Strategy

Dr. Anthony Waddle, a Schmidt Science Fellow at Macquarie University’s Applied BioSciences and the lead author of the study, highlights the significance of their research: “In the 25 years since chytrid was identified as a major cause of the global collapse of amphibian populations, our results are the first to provide a simple, inexpensive, and widely applicable strategy to buffer frogs against this disease.”

Findings and Methodology

The research team discovered that artificial ‘hotspot’ shelters made from readily available materials, such as bricks and PVC greenhouses, can help frogs quickly ‘bake off’ infections with the chytrid fungus. These hotspots allow frogs to heat their bodies to a temperature that destroys the fungal infections.

When frogs used these hotspot shelters, chytrid infections were significantly reduced. “The whole thing is like a mini med spa for frogs,” says Dr. Waddle. The study also demonstrated that frogs surviving a chytrid infection could develop a form of acquired immunity, making them more resistant to future infections.

Implications and Scalability

Senior author Professor Rick Shine, from Macquarie University’s School of Natural Sciences, emphasizes the potential impact of their findings: “Chytrid isn’t going away, but our behavioral ecology intervention can help endangered amphibians co-exist with chytridiomycosis in their ecosystems.” The simplicity and low cost of these hotspot shelters mean the strategy can be easily scaled up with community involvement.

Dr. Waddle adds, “Lowering mortality rates and boosting their immunity to chytrid is the key to protecting amphibians from this disease, which is now endemic around the world.”

Cross-Institutional Collaboration and Future Prospects

Professor Lee Skerratt, Professorial Fellow in Wildlife Bioscience at the University of Melbourne, underscores the importance of collaboration in tackling this global problem: “This research has great potential to be extrapolated to other endangered frog species threatened by chytridiomycosis, and demonstrates the value of cross-disciplinary and cross-institutional collaboration.”

Conclusion

The study’s findings represent a significant breakthrough in amphibian conservation, offering a practical and scalable solution to mitigate the impacts of chytridiomycosis. By providing simple ‘hotspot’ shelters, researchers have found a way to reduce infections and enhance the immunity of endangered frog populations, paving the way for more effective conservation strategies in the fight against this devastating disease.